cwatters:
That is basically correct. You use a balanced control input, called a doublet, to set the aircraft moving about the axis of interest. You use a balanced input, such as left pedal, back to neutral, right pedal, back to neutral, so you can induce pure oscillating movement, and not just a steady change in slip angle.
Then you sit back and watch, without further pilot inputs. You are primarily watching the amplitude of each successive cycle in yaw (or whatever), to see if it's getting smaller (damped) or bigger (divergent). If it is divergent, then the pilot and the test engineer try to see who can go the most cycles before chickening out and calling for control inputs. (Just joking, of course).
By the way, these are maneuvers for professional flight test people. Please don't try them at home.